A new digital revolution
is coming, this time in fabrication. It draws on the same insights that led to
the earlier digitizations of communication and computation, but now what is
being programmed is the physical world rather than the virtual one. Digital
fabrication will allow individuals to design and produce tangible objects on
demand, wherever and whenever they need them. Widespread access to these technologies
will challenge traditional models of business, foreign aid, and education.

The
roots of the revolution date back to 1952, when researchers at the
Massachusetts Institute of Technology (mit) wired an early digital computer to a milling machine,
creating the first numerically controlled machine tool. By using a computer
program instead of a machinist to turn the screws that moved the metal stock,
the researchers were able to produce aircraft components with shapes that were more
complex than could be made by hand. From that first revolving end mill, all
sorts of cutting tools have been mounted on computercontrolled platforms,
including jets of water carrying abrasives that can cut through hard materials,
lasers that can quickly carve fine features, and slender electrically charged
wires that can make long thin cuts.

Today,
numerically controlled machines touch almost every commercial product, whether
directly (producing everything from laptop cases to jet engines) or indirectly
(producing the tools that mold and stamp mass-produced goods). And yet all
these modern descendants of the first numerically controlled machine tool share
its original limitation: they can cut, but they cannot reach internal structures.
This means, for example, that the axle of a wheel must be
manufactured separately from the bearing it passes through.

In
the 1980s, however, computer-controlled fabrication processes that added rather
than removed material (called additive manufacturing) came on the market.
Thanks to 3-d printing, a bearing and an axle could be built by the same
machine at the same time. A range of 3-d printing processes are now available,
including thermally fusing plastic filaments, using ultraviolet light to
cross-link polymer resins, depositing adhesive droplets to bind a powder,
cutting and laminating sheets of paper, and shining a laser beam to fuse metal
particles.

Businesses
already use 3-d printers to model products before producing them, a process
referred to as rapid prototyping. Companies also rely on the technology to make
objects with complex shapes, such as jewelry and medical implants. Research
groups have even used 3-d printers to build structures out of cells with the
goal of printing living organs.